View Full Version : animating a simple extrusion along a complex path

02-27-2013, 01:55 PM

I want to make it look as if this "crack" is growing from one end, segment by segment. There are almost 500 points and line segments, so to do this as an MTSE morph would be a considerable pain. Using a mask to reveal it would be even more cumbersome, as multiple masks would be needed and the leading edge would have to angle along the path. I know there must be some way to use this object as a path to morph another object, but it's something I've never done. I'd be grateful for any help.


02-27-2013, 02:18 PM
If your object has been generated procedurally,
you could try Shifter node from DP Kit.


02-27-2013, 04:10 PM
How 'bout this....

"Straighten" out your object with UV creeper. You end up with a perfectly straight map in V (both U and V really, but you only need to be concerned with V for this).
Use that map and the V output as input to a gradient stepped over time on transparency channel. You can set up one step that repeats or vary it as you wish.

I started out with a curvy tube..... the reveal is stepped over time. Don't know where I got the impression that you wanted a "stuttered" effect, but that's what I did (very much on purpose in this example).
If that is the desired direction.... with 500 segments, you might have a hard time making each section a step without the reveal looking pretty smooth (unless you have a lot of time). You might want to do bigger chunks than each facet.

My initial idea was to use a weight map to drive the gradient, but my Weight Outward plug was giving me fits with this simple object (:stumped:). Anyway, you can use a weight map too. :thumbsup:

02-27-2013, 04:30 PM
Yup, weight map works too....

Here's the set up. I've got a multiply in there because you said it was 500 steps.....

02-27-2013, 10:40 PM
found a fractal.....
used a weight map this time....


02-28-2013, 06:41 AM
Thank you so much JoePoe and dpont for helping me out. I really appreciate the generosity of LW users. I'll have a go at it-- the fractal animation is very much along the lines of what I'm looking for...

02-28-2013, 10:23 AM
cool, glad the fractal was close.

2 notes re: the second animation....
1) As suspected the stair step envelope didn't look quite right (to me) on the fractal (the one I used has 700+ facets), so I changed the envelope to a straight ramp up.
2) in order to save on poly count on a 700+ faceted path for an extrusion, I kept the fractal a simple 2point poly chain and used the negative line technique to give it "dimension". (I seem to be using that trick a lot lately... :))

02-28-2013, 03:06 PM
There's also SG_Fertilizer.p (uses a weight map of 100 on the whole object and 0 on the verts that mark the beginning of growth). Simple.


02-28-2013, 10:43 PM
As Chrusion says, Fertilizer is the tool. There exists a new 64 bit bersion too. Great tool, saved my butt many times.

02-28-2013, 10:54 PM
double post, sorry

03-26-2014, 08:02 AM
Yup, weight map works too....

Here's the set up. I've got a multiply in there because you said it was 500 steps.....

Would be super nice if you could share the scene JoePoe :)